A number of factors, including obesity, oral hygiene, drinking and smoking, have been shown to alter a persons ability to taste. In the new work, published today in the journal BMC Neuroscience, Yuriy P. Zverev of the University of Malawi investigated how overnight fasting affected the taste buds of healthy males who neither smoked nor drank. After eating a set meal for dinner, the subjects skipped breakfast and were subsequently tested on their ability to taste salty, sweet and bitter solutions of varying concentrations. The participants returned later in the day, about an hour after eating lunch, and repeated the blind taste tests. When hungry, the men detected lower concentrations of sugar and salt than they did after a meal, but their ability to detect bitter compounds remained unchanged.
Zverey posits that the consistency of a persons sensitivity bitterness may be part of a defensive mechanism for avoiding eating something dangerous because of hunger. "While sweet and salty tastes are indicators of edible substances and trigger consumption," he says, "a bitter taste indicates a substance which is not suitable for consumption and should be rejected."